Petunias are showy members of the tomato family grown as garden flowers, and like many garden flowers they have become semi-wild denizens of our city. The wild ones are usually pink or white. This plant was growing from a sidewalk crack on the South Side. The garden petunia is a hybrid of Petunia axillaris and Petunia integrifolia, but the hybrid comes true from seed, although the wild seedlings generally lose the more spectacular variations of the cultivated hybrids.